Improvement of dislocation density in thick CVD single crystal diamond films by coupling H2/O2 plasma etching and chemo-mechanical or ICP treatment of HPHT substrates

H2/O2 plasma treatments offer advantages over other etching processes of diamond as a technique to prepare the substrate's surface prior to homoepitaxial CVD diamond growth particularly in the case of thick films. It allows removing surface defects induced by polishing, thus leading to an improved morphology and limiting the stress within the grown crystal. Nevertheless, this treatment induces surface roughness leading to dislocation formation when CVD growth is initiated. In this paper we combined H2/O2 plasma etching with smoother surface treatment such as RIE-ICP etching or Chemo-Mechanical Polishing and we showed a significant reduction in dislocation density of the thick CVD epitaxial layers.